Beds: (i) The mattresses were Chinese-style - ie they were hard - this is likely OK for some, but likely not for many (however, if you have travelled in China, you may have adapted to such mattresses) (ii) I always prefer, from a hygiene-perspective, when hotels use some form of mattress protector, rather than when sheets are laid directly onto the mattress, as here.
Prices: Discussions on price are always difficult in Nepal and KTH was no different in this regard. When I sought to stay on a second occasion with KTH (booked verbally, rather than via Booking.com) they sought initially to charge me more for the room than my initial stay booked via Booking.com and it was necessary to negotiate down to the Booking.com price. This was annoying.
Karma Traveller's Home (KTH) offers reasonable value for money - it has some defects, but you can't expect excellence for the price.
Kathmandu has frequent power cuts. KTH has solar power and solar hot water - this means that there is the possibility of some electricity for one light in your room and some hot water during the power cuts provided there has been sufficient sunlight over the prior days. The WIFI (which only works well in but a limited number of rooms, but OK in common areas) also runs off the solar, so it may also be functional during the power cuts.
On the first day, there was no room available of the type that I'd reserved on Booking.com (poor scheduling practice on KTH's part) and I had to stay in a lower quality (cheaper) room. However KTH tried to make amends by offering me a discount on the price of the cheaper room - which was a reasonable offer in the circumstances (albeit the offer was not made immediately, as perhaps it should have been, but rather took a little bit of time to negotiate to).
If you stay for multiple days, you need to be aware that your room is not attended to by the staff - you need to ask if you want anything done (eg bin emptied, more toilet paper). However, after you ask, I found that the staff were happy to respond to any request.